Vehicles have employed a number of different forms of keyless entry systems that can allow a user to lock or unlock a vehicle door without the use of a key and lock combination. Such systems can include remote controls and various forms of digital keypads. In general a digital keypad with buttons that correspond to one or more integer values that can be depressed in a sequence corresponding to a known access code. Most often, the values of the buttons are fixed, meaning that an observer can determine the code being entered by tracking the sequence of buttons pressed by a user accessing the vehicle. Other forms of digital code entry may also be susceptible to code determination by observing any fixed sequences that they employ for gaining access to a vehicle. Accordingly, further advances may be desired.